Fix KMS/DRM on ArchyPie

[V0rt3x667]

At present ArchyPie is only functional on devices that are running either x11 or Wayland. EmulationStation & AttractMode do not work under KMS/DMS on x86 and probably are not working on Raspberry Pis. The Raspberry Pi 2,3 & 4 no longer use the propriety Broadcom drivers on Arch Linux Arm. It would also be nice if x86 could also run ArchyPie without x11/Wayland where possible.

• Set up Raspberry Pi 2 for testing
• Restore missing backend functions & modules from RetroPie
• Add the custom SDL 1.2 Backwards Compatibility & SDL2 libraries provided by RetroPie for KMS
• Get at least one frontend working on x86 with KMS

[V0rt3x667]

Testing on a Raspberry Pi stock SDL2 uses KMS/DRM without further modification. EmulationStation & RetroArch run fine. Attract-Mode does not however as the version of SFML shipped by Arch Linux Arm does not appear to have been built with DRM enabled. Further testing is required. A custom version of SDL2 will still be required for x86 using KMS/DRM only.

[V0rt3x667]

After testing a x86_64 Arch Linux build in VirtualBox it appears that SDL2 versions 2.30.8 & 2.30.9 have resolved KMS/DRM detection issues. EmulationStation runs well without further modification. Unfortunately I have not been able to test this on real x86_64 hardware yet.